Print paper separating apparatus and method thereof

ABSTRACT

A method and apparatus are provided for separating a top print paper from a stack of print papers using print paper buckling. The print paper separating method and apparatus include a transporting element for transporting the print paper by contacting the top of the stack of print papers. A plurality of elastic fibers are provided to induce buckling of the print paper using an elastic force. The elastic fibers may be provided with an electrical ground.

This application claims the benefit under 35 U.S.C. § 119(a) of Korean Patent Application No. 10-2004-0115034, filed on Dec. 29, 2004 in the Korean Intellectual Property Office, the entire disclosure of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a print paper separating apparatus and method. More particularly, the present invention relates to a print paper separating apparatus and method that can separate print paper one by one from a stack of print papers.

2. Description of the Related Art

Generally, print papers are separated using equipment employing friction coefficients or buckling to separate print papers from a stack of print papers. FIG. 1 shows an example of a conventional separating apparatus using friction coefficients. Referring to FIG. 1, a transport roller 1 is in contact with the top of a stack of print papers S. A separating roller 2 is in contact with a friction plate 3, which is disposed at the front portion of the stack of print papers S. An elastic element 4 pushes friction plate 3 towards the separating roller 2. When the transport roller 1 rotates, a plurality of print papers P are transported between separating roller 2 and friction plate 3. Here, a friction coefficient μ1 occurs between the print papers P and separating roller 2, a friction coefficient μ2 occurs between friction plate 3 and the print papers P, and a friction coefficient μ3 occurs between the print papers P themselves, such that μ1>μ2>μ3. Therefore, even if a plurality of print papers P are transmitted between separating roller 2 and friction plate 3, only one print paper P1 contacting the separating roller 2 is separated from the stack of print papers S and passes through separating roller 2 and friction plate 3. When the separating apparatus illustrated in FIG. 1 is used over a long period of time, the separating roller 2 and the friction plate 3 become contaminated by external matter, such as paper powder and dust. When separating roller 2 and friction plate 3 are contaminated, friction coefficients μ1 and μ2 decrease, which can lead to double feeding or multiple feeding. In addition, static electricity is produced when print papers P are rubbed between separating roller 2 and friction plate 3. Static electricity causes print papers P to strongly adhere together, thereby reducing the separating ability of the apparatus.

FIG. 2 shows an example of a conventional separating apparatus using buckling. Referring to FIG. 2, a transport roller 1 is in contact with the top of a stack of print papers S. A resistance member 5, installed at a predetermined tilt angle A, is placed at the front portion of the stack of print papers S. When the transport roller 1 rotates, a plurality of print papers P will typically start to move in the direction of rotation. The friction between the transport roller 1 and print papers P is higher than the friction between the individual print papers. Therefore, when the leading edge of print papers P come into contact with resistance member 5, only print paper P1, the paper in contact with transport roller 1 at the top of the stack S, slips forward from the rest of the print papers P and is thus transported. Then, only the front end of print paper P1 is bent and a curve C1 is created, as illustrated in FIG. 2. As the transport roller 1 continues to rotate, the print paper P1 bends with a larger radius, as shown by curve C2. After continued forward movement of paper P1 caused by forward rotation of transport roller 1, curve C2 instantly straightens, as indicated by C3, thereby separating and transporting only print paper P1. Hereinafter, the condition of curve C3 instantly straightening will be called “buckling.”

The tilt angle A of resistance member 5 is set to be appropriate for commonly used plain print papers. When trying to separate thick print paper having strong stiffness using the tilt angle A appropriate for plain print papers, an error can occur in which the print paper is not transported because the buckling process of C1, C2, C3 cannot be performed due to the tilt angle A. In this case, a driving motor (not shown), which drives transport roller 1, may be overloaded. In addition, double feeding or multiple feeding can occur or the front edge of the print paper can be damaged because the buckling process has not been performed. In the case of a thin print paper, the buckling process cannot be successfully carried out because the tilt angle A, and an accordion jam may occur.

SUMMARY OF THE INVENTION

The present invention provides a print paper separating apparatus and method using stiffness of a print paper that can safely separate and transport a plain print paper, a thick print paper with relative strong stiffness, and a thin print paper with relative weak stiffness.

According to an exemplary aspect of the present invention, there is provided a print paper separating apparatus that separates a top sheet of print paper from a stack of print papers using buckling. The apparatus comprises a transport element for transporting the print paper by contacting a top sheet, and a plurality of elastic fibers for inducing buckling by using an elastic force imparted by contacting the front end of the print paper stack. For example, a plurality of elastic fibers are arranged in a tilt with respect to the stack of print papers. The paper separating apparatus may further comprise an aligning wall for aligning the front ends of the stack of print papers. In an exemplary embodiment, the aligning wall is parallel to the front end, or tips, of the plurality of elastic fibers. In another exemplary embodiment, the elastic fibers are grounded in order to discharge static electricity accumulation.

According to another exemplary aspect of the present invention, there is provided a print paper separating method for separating a top sheet of paper from a stack of paper using buckling. The method comprises inserting the stack of paper at a tilt angle relative to a plurality of elastic fibers, the angle being selected to facilitate paper separation within the stack, each elastic fiber having a distal tip and adapted to induce buckling by elastic force. The method may further comprise rotating a transport roller to cause the top sheet of paper to advance in a direction towards the elastic fibers, wherein the elastic fibers bend in response to contact with the advancing paper until the advancing paper applies a level of force against the elastic fibers so as to cause the paper to buckle and transport over the top of the elastic fibers.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other exemplary features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which:

FIG. 1 shows an example of a conventional separating apparatus using friction coefficients;

FIG. 2 shows an example of a conventional separating apparatus using buckling;

FIGS. 3 and 4 illustrate views of a print paper separating apparatus in accordance with an embodiment of the present invention;

FIG. 5 shows a first separation by a tilt between an elastic fiber and a stack of print papers;

FIGS. 6A through 6C, 7, 8A through 8C illustrate views of the print paper separating process in accordance with an embodiment of the present invention; and

FIG. 9 illustrates the self-alignment process of the elastic fiber.

Throughout the drawings, like reference numbers should be understood to refer to like elements, features, and structures.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Exemplary embodiments of the present invention will now be described more fully with reference to the accompanying drawings.

In one exemplary embodiment of the present invention, illustrated in FIG. 3, a print paper separating apparatus comprises a transport roller (in other words, a transport element) 10 contacting the top of a stack of print papers S for transporting print papers P. The apparatus further comprises a plurality of elastic fibers 20 contacting the front end of stack S to induce buckling of the print papers P. The plurality of elastic fibers 20 are arranged in a two-dimensional configuration, for example, in a form of a brush, as illustrated in FIG. 4. The stack of print papers S and the elastic fibers 20 may be tilted at a predetermined angle with respect to each other. The print paper separating apparatus further comprises an aligning wall 30. The aligning wall 30 is placed slightly back, or recessed, from the distal tips of elastic fibers 20. The aligning wall 30 may be parallel to the distal tips of elastic fibers 20. The elastic fibers 20 may be manufactured with, for example, metal, plastic, or fibers having elasticity. Although not illustrated in FIGS. 3 and 4, the elastic fibers 20 and the aligning wall 30 may be installed at a plurality of locations along the front edge of print papers P.

As illustrated in FIG. 5, a first separation occurs when the front ends of print papers P are inserted between each of the elastic fibers 20. The papers P are inserted at an angle relative to the elastic fibers 20 to facilitate separation of the individual paper sheets. Here, the elastic fibers 20 may bend slightly due to the weight of the print papers P. The aligning wall 30 prevents the ends of the print papers P from being inserted too deeply between each of the elastic fibers 20 by contacting the front ends of the print papers P and serving as a stop. In addition, the aligning wall 30, which is parallel to the distal tips of elastic fibers 20, serves to equalize insertion of each print paper P between each of the elastic fibers 20.

The following is an example of a separating process conducted by the print paper separating apparatus in the present exemplary embodiment.

When the transport roller 10 rotates, print papers below the top print paper P1, such as print papers P2 and P3, start to move together with print paper P1, as illustrated in FIG. 6A. The front ends of print papers P1, P2, and P3 may contact an elastic fiber (or an elastic fiber row) 20-1. A friction coefficient between the transport roller 10 and print paper P1 is higher than the friction coefficient between print paper P1 and print paper P2. Therefore, after the front ends of the print papers P1, P2, and P3 come into contact with the elastic fiber 20-1, slipping occurs between the print paper P1 and print paper P2. As a result, only print paper P1 continues to be transported. Fiction exists between print paper P1 and print paper P2, and print paper P2 and print paper P3. Therefore, the transportation force of transport roller 10 is transmitted to print papers P2 and P3 as well. This causes print papers P2 and P3 to move slightly.

At first, print paper P1 does not bend due to the stiffness of the paper. Instead, elastic fiber 20-1 bends as print paper is pushed. When the elastic force of elastic fiber 20-1 and the stiffness of print paper P1 become equal, the elastic fiber 20-1 stops bending and the front end of print paper P1 begins to bend, forming curve D1 as illustrated in FIG. 6B. As transport roller 10 continues to rotate, the radius of curve D1 increases to become curve D2, thereby producings buckling. Eventually, as shown in FIG. 6C, print paper P1 continues to be transported over the top of elastic fiber 20-1. When print paper P1 is transported over the top of elastic fiber 20-1, the force applied by print paper P1 to elastic fiber 20-1 is removed, and elastic fiber 20-1 recovers to its original position, as shown by the transition from the dotted lines in FIG. 6C to the solid lines. The recovery of elastic fiber 20-1 pushes print papers P2 and P3 in the opposite direction to the transport direction of print paper P1. Thus, print papers P2 and P3 are stopped by elastic fiber 20-1 and not transported; only print paper P1 is separated and transported.

In addition to separation through buckling, a thick print paper can be separated through the following process. Referring to FIG. 7, a transportation force F of the transport roller 10 applied to the print paper P1 at a contact point of elastic fibers 20-1 and print paper P1 can be resolved into a tangential component Ft and a normal component Fn, at the elastic fiber 20-1. Here, if the tangential force component Ft is larger than the coefficient of friction μ4 between print paper P1 and elastic fiber 20-1 multiplied by the normal force component Fn, then print paper P1 slides over the top of the elastic fiber 20-1 and is transported as illustrated by the dotted line in FIG. 7. When print paper P1 is transported over the top of elastic fiber 20-1, the force applied by print paper P1 to elastic fiber 20-1 is removed, and elastic fiber 20-1 recovers to its original position. The recovery of elastic fiber 20-1 pushes print papers P2 and P3 in the opposite direction to the transport direction of print paper P1. Thus, print papers P2 and P3 are stopped by elastic fiber 20-1 and not transported; only print paper P1 is separated and transported.

As illustrated in FIG. 8A, each of the print papers P1, P2, and P3 may contact different elastic fibers (or elastic fiber rows) 20-1, 20-2, 20-3. Since the friction coefficient between transport roller 10 and print paper P1 is higher than the friction coefficient between print paper P1 and print paper P2, slipping occurs between print paper P1 and print paper P2. As a result, only print paper P1 continues to be transported. The transportation force of transport roller 10 also affects print papers P2 and P3. As a result, print papers P2 and P3 may be slightly transported.

As illustrated in FIG. 8B, at first print paper P1 does not bend due to the stiffness of the paper. Instead, elastic fiber 20-1 bends as it is pushed by print paper P1. Elastic fibers 20-2 and 20-3 may also bend slightly as print papers P2 and P3 are transported. However, elastic fiber 20-1 is bent the most. When the elastic force of elastic fiber 20-1 and the stiffness of print paper P1 are in balance, elastic fiber 20-1 stops bending further and the front end of print paper P1 begins to bend, forming curve Dl as illustrated in FIG. 8B. As transport roller 10 continues to rotate, the radius of curve D1 increases to become curve D2, thereby producing buckling. Eventually, as shown in FIG. 8C, print paper P1 continues to be transported over the top of elastic fiber 20-1. When print paper P1 is transported over the top of elastic fiber 20-1, the force applied by print paper P1 to elastic fiber 20-1 is removed, and elastic fiber 20-1 recovers to its original location. As elastic fiber 20-1 recovers to its original location, print papers P2 and P3 are slightly pushed in the opposite direction to the transportation direction of print paper P1. Thus, print papers P2 and P3 are stopped by elastic fiber 20-1 and are not transported; only print paper P1 is separated and transported.

To reduce transport roller 10 driving motor (not shown) overload, the tilt angle between the front ends, or leading edge, of print papers P and elastic fibers 20 may be larger for printing plain print paper of moderate thickness than for printing think print paper. Alternatively, to prevent an accordion jam and double feeding or multiple feeding, the tilt angle for separating thin print papers may be smaller than the tilt angle for separating the plain print papers of moderate thickness. In the print paper separating apparatus according to an embodiment of the present invention, the elastic fibers 20 are self-aligned to form an appropriate tilt angle with the front ends of print papers P by reacting to the stiffness of the print papers P.

Referring to FIG. 9, when print papers P are plain print papers of moderate thickness, the elastic fiber 20 will bend as indicated by 20 a to balance with the stiffness of the print. The elastic fiber 20 will bend further, as indicated by 20 b, when the print paper P is think print paper with a strong stiffness; and elastic fiber 20 will bend less, as indicated by 20 c, when the print paper P is thin print paper with a weak stiffness. The tilt angle between the front end of print paper P and elastic fiber 20 is different for each of the three thicknesses of print paper P. The tilt angle is defined by an angle formed between a tangent line La, Lb, or Lc of elastic fiber 20 and a line Ea, Eb or Ec perpendicular to print paper P at a contact point of the front end of print paper P and the elastic fiber 20. If the tilt angle is defined as Ba, Bb, or Bc, respectively, they satisfy Bb>Ba>Bc. Because the elastic fibers 20 naturally bend to an appropriate tilt angle when adjusting to the stiffness of print papers P, numerous print papers P with different stiffness can be successfully separated, and thus prevent damage to the front ends of the papers.

In reference to FIG. 4, an electrical ground may be provided for the plurality of elastic fibers 20. For example, fiber holder 40, in which the plurality of elastic fibers 20 are installed, may be constructed of electrically conductive material to which a ground connection can be made. Thus, in the process of separating the print papers P, any static electricity accumulated on the print papers P due to friction between the papers is discharged to ground, thereby reducing adhesion between the print papers caused by static electricity.

As disclosed above, the following effects may be achieved with a print paper separating apparatus and method in accordance with exemplary embodiments of the present invention.

According to an exemplary implementation, since an elastic fiber naturally bends to an appropriate angle by accommodating the stiffness of print paper, various print papers with different degrees of stiffness can be successfully separated and damage to the front end of the print paper can be prevented.

According to another exemplary implementation, by installing a plurality of elastic fibers to tilt relative to a stack of print papers, the top ends, or leading edge, of the print papers insert between each of the plurality of elastic fibers, thereby completing a first separating process. As a result, the possibility of double feeding or multiple feeding is reduced.

According to another exemplary implementation, by installing an aligning wall slightly recessed from the distal tip of the elastic fibers, the front ends of the print papers are prevented from being inserted too deeply between each of the plurality of elastic fibers.

According to another exemplary implementation, by providing an electrical ground for the elastic fibers, double feeding or multiple feeding caused by static electricity is prevented.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims. 

1. A sheet paper separating apparatus, comprising: a transporting element for transporting paper sheets by contacting a top sheet of a stack of the paper sheets and causing at least the top sheet of the stack of paper sheets to transport; and a plurality of elastic fibers for inducing buckling of the at least the top sheet of the stack of paper using an elastic force, contact a front end of the at least the top sheet of the stack of paper sheets.
 2. The print paper separating apparatus of claim 1, wherein the plurality of the elastic fibers are arranged at a tilt angle with respect to the stack of paper sheets.
 3. The print paper separating apparatus of claim 2, further comprising, an aligning wall recessed from the plurality of the elastic fibers, wherein front ends of the stack of paper sheets are aligned by coming into contact with the aligning wall.
 4. The print paper separating apparatus of claim 3, wherein the plurality of the elastic fibers comprise respective distal tips, and the aligning wall is parallel to the distal tips of the plurality of elastic fibers.
 5. The print paper separating apparatus of claim 1, wherein the plurality of elastic fibers are electrically coupled to ground.
 6. A method of separating a top sheet of paper from a stack of paper sheets, the method comprising: inserting a stack of paper sheets at a tilt angle relative to a plurality of elastic fibers, the elastic fibers being adapted to induce buckling by elastic force; and advancing the top sheet of the stack of the paper sheets toward the elastic fibers, wherein the elastic fibers bend in response to contact with at least the advancing top sheet until the at least the advancing top sheet applies a level of force against the elastic fibers so as to cause the top sheet to buckle and transport over the elastic fibers.
 7. The method of claim 6, further comprising the tilt angle adjusting to accommodate paper thickness. 